The TurboGrafx-16 has an 8-bit CPU and a dual 16-bit GPU; and is capable of displaying 482 colors simultaneously, out of 512. With dimensions of 14 cm×14 cm×3.8 cm (5.5 in×5.5 in×1.5 in), the NEC PC Engine once held the record for the world's smallest game console.[2]

In the United Kingdom, Telegames released a slightly altered version of the American model simply as the TurboGrafx around 1990 in extremely limited quantities.[3] Although there was no full-scale PAL region release of the system, imported PC Engine consoles were largely available in France and Benelux through major retailers thanks to the unlicensed importer Sodipeng (Société de Distribution de la PC Engine, a subsidiary of Guillemot International).[4]

Two major revisions, the PC Engine SuperGrafx and the TurboDuo, were released in 1989 and 1991, respectively. The entire series was succeeded by the PC-FX in 1994, which was only released in Japan.

The TurboGrafx-16 was a collaborative effort between the relatively young Hudson Soft (founded in 1973) and NEC. NEC's interest in entering the lucrative video game market coincided with Hudson's failed attempt to sell designs for then-advanced graphics chips to Nintendo.[5]

CoreGrafx II with Super-CD-Rom² unit

The TurboGrafx-16 was the first video game console to have a CD-ROM peripheral, and to use CD-ROM as a storage medium for video games.[6][7] NEC released the CD-ROM²(シーディーロム2,Shī Dī Romu Romu?) in Japan on December 4, 1988,[8] and released the TurboGrafx-CD in the United States on August 1, 1990. NEC was also the first to market a game console with an integrated CD-ROM drive: the TurboDuo of 1991.

The TurboGrafx-16 was released in the New York City and Los Angelestest market in late August 1989. Initially, the TurboGrafx-16 was marketed as a direct competitor to the NES and early television ads touted the TG-16's superior graphics and sound. These ads featured a brief montage of the TG-16's launch titles: Blazing Lazers, China Warrior, Vigilante, Alien Crush, etc. The TG-16 was also in direct competition with the Sega Genesis, which had had its own New York/Los Angeles test-market launch two weeks prior, on August 14.[10] The Genesis launch was accompanied by an ad campaign mocking NEC's claim that the TurboGrafx-16 was the first 16-bit console.

NEC claimed that it had sold 750,000 TG-16 consoles in the United States, and 500,000 CD-ROM units worldwide, by March 1991.[11] That year NEC released the PC Engine Duo, a model which could play both TurboGrafx-16 cards and CDs. The console was licensed to Turbo Technologies Incorporated, who released it in North America in 1992 as the TurboDuo. The unit came into competition with the Sega CD, which was released almost immediately after. Turbo Technologies ran comic book ads featuring Johnny Turbo. The ads mocked Sega, and emphasized that though the TurboDuo and Sega CD had the same retail price, the TurboDuo was a standalone console and included five pack-in games, whereas Sega CD buyers needed to purchase separately sold games and Sega Genesis units before they could use the system.

However, the North American console gaming market continued to be dominated by the Super Nintendo and Genesis rather than the new CD-based consoles. In May 1994 Turbo Technologies announced that it was dropping support for the Duo, though it would continue to offer repairs for existing units and provide ongoing software releases through independent companies in the USA and Canada.[12]

New commercial titles were released for the PC Engine up until 1999.[13]

The TurboGrafx-CD (PC Engine CD in Japan) is an add-on console which, when attached to a standard TurboGrafx-16, can play CD games and audio CDs. In addition to small BIOS updates, two "upgrades" to the CD-ROM² would follow: the Super CD-ROM²(スーパーシーディーロム2,Sūpā Shī Dī Romu Romu?) and its "Super System Card" (スーパーシステムカード,Sūpā Shisutemu Kādo?) (added 192KB of RAM); and the Arcade CD-ROM²(アーケードシーディーロム2,Ākēdo Shī Dī Romu Romu?) and its "Arcade Cards" (アーケードカード,Ākēdo Kādo?) (Pro and Duo, added 2MB of RAM). These were not compatible with the TurboGrafx-16 without an adapter.

The SuperGrafx is a variation of the standard PC-Engine hardware. This system is nearly identical to the original PC Engine, except it has a second HuC6270A (VDC), a HuC6202 (VDP) to combine the output of the two VDCs, four times as much RAM, twice as much video RAM, and a second layer/plane of scrolling. The CPU, sound, and color palette were not upgraded, making the expensive price tag a big disadvantage to the system. NEC also decided to not include the extra two video chips in the all-in-one Duo replacement system. Only five exclusive SuperGrafx games and two hybrid games (Darius Plus and Darius Alpha took advantage of the extra video hardware if played on a SuperGrafx) were released, and the system fell into obscurity.

Other members of the PC Engine family include the Shuttle, the LT (a laptop version similar to the Game Boy Advance SP, but considerably larger), the CoreGrafx I and II, the Duo R and the Duo RX. Contrary to popular belief, the CoreGrafx is not a European version of the PC Engine. It is simply a reengineered version of the original (white) PC Engine with an AV output instead of the original model's RF output. The PC Engine and its derivatives were not officially released in Europe, although many systems and most accessories and games were available as imports.

The TurboExpress is a portable version of the TurboGrafx, released in 1990 for $249.99 (the price was briefly raised to $299.99, soon dropped back to $249.99, and by 1992 it was $199.99). It was the most advanced handheld of its time and could play all the TG-16's HuCard games five years before the Sega Nomad could do the same for Sega Genesis games. Its Japanese equivalent is the PC Engine GT'. It has a 2.6-inch (66 mm) backlit, active-matrix color LCD screen, the most advanced on the market for a portable video game unit at the time. The screen contributed to its high price and short battery life, however. Its keypad layout is similar to that of the original Game Boy. It shares the capabilities of the TurboGrafx, giving it 512 available colors (9-bit RGB), stereo sound, and the same custom CPU at 7.15909 MHz. The optional "TurboVision" TV tuner included RCA audio/video input, allowing the user to use TurboExpress as a video monitor. The "TurboLink" allowed two-player play. Falcon, a flight simulator, included a "head-to-head" dogfight mode that could only be accessed via TurboLink. However, very few games offered co-op play modes especially designed with the TurboExpress in mind.

In 1991 NEC Home Electronics released the TurboDuo (PC Engine Duo in Japan). The system combined the PC Engine and the Super CD-ROM² into a single unit. The system can play audio CDs, CD+Gs, CD-ROM2 and Super CD-ROM² games as well as standard HuCards. The North American release was originally bundled with one control pad, an AC adapter, RCA cables, Ys Book I & II (a CD-ROM² title), and a Super CD-ROM² including Bonk's Adventure, Bonk's Revenge, Gate of Thunder and a secret version of Bomberman accessible via an easter egg. The system was also packaged with one random HuCard game which varied from system to system (Dungeon Explorer was the original HuCard pack-in for TurboDuo, although many titles were eventually used, such as Irem's Ninja Spirit and Namco's Final Lap Twin, and then eventually a random pick). The Super System Card required for some games when using the original CD add-on as well as some of the Japanese variants of the TurboGrafx was built into the Duo rather than requiring the card to be inserted at all times when playing CD games.

The X1 Twin is a combination of X1 computer and PC Engine. It only plays HuCards. The PC-KD863G, a computer (RGB) monitor with a built-in PC Engine, likewise only plays HuCards. Pioneer Corporation's Pioneer LaserActive supports an add-on module which allows the use of PC Engine games (HuCard, CD-ROM² and Super CD-ROM²) as well as new "LD-ROM²" titles that only work on this device. NEC also released their own LaserActive unit and PC Engine add-on module, under an OEM license.[14] Only eleven LD-ROM2 titles were produced, with only three of them released in North America.

The TurboGrafx-16 was released in South Korea by a third party under the name Vistar 16.[15]

Various PC Engine Shuttle clones exist, with varying levels of compatibility with original PC-Engine games. One of the more common types is the "PC Boy".[citation needed]

The PC Engine was never officially released in continental Europe, but some companies imported them and made SCART conversions on a moderate scale. In France, Sodipeng imported Japanese systems and added an RGB Cable called "AudioVideo Plus Cable".[citation needed] This mod improved the original video signal quality extensively and made the consoles work with SECAM televisions. In Germany, several importers sold converted PC Engines with PAL RF as well as RGB output.[citation needed] The connectors and pinouts used for the latter were frequently compatible with the Amiga video port, with two unconnected pins used for the audio channels.[citation needed]

The TurboGrafx-16 had only one controller port, so any multiplayer games required the TurboTap accessory.

All PC Engine systems support the same controller peripherals, including pads, joysticks and multitaps. Except for the Vistar, Shuttle, GT, and systems with built-in CD-ROM drives, all PC Engine units shared the same expansion connector, which allowed for the use of devices such as the CD-ROM unit, game saves and AV output.

The TurboGrafx and Vistar units use a different controller port than the PC Engines, but adaptors are available and the protocol is the same. The TurboGrafx offers the same expansion connector pinout as the PC Engine, but has a slightly different shape so peripherals must be modified to fit.

The Arcade Card Pro is designed for the original CD-ROM² and Super CD-ROM² peripherals, adding the 2304 kB of RAM required by Arcade CD-ROM² games. The Arcade Card Duo is for the PC-Engine Duo/R/RX consoles and adds 2048 kB RAM, because the PC-Engine Duo series of systems have 256K of RAM built-in.

All PC Engine hardware outputs video in NTSC format, including the European TurboGrafx; it generates a PAL-compatible video signal by using a chroma encoder chip not found in any other system in the series.

The PC Engine is a relatively compact video game console, owing to an efficient three-chip architecture and its use of small ROM cartridges called HuCards (Turbo Chips in North America). Hudson Soft developed the HuCard (Hudson Card) from the Bee Card technology it piloted on the MSX. HuCards, or TurboChips in the US, are about the size of a credit card, but slightly thicker. They are not unlike the slim cartridge reserved for low-budget game releases on the Sega Master System. The largest Japanese HuCard games were up to 20 Mbit in size.

With only one exception, the PC Engine SuperGrafx, all PC Engine hardware could play the entire HuCard library, and every CD system could play all of the licensed CD games - with the right system card. Some unlicensed CD games by Games Express required a Duo system, due to their games requiring both a special system card packaged with the games and the 256 kB of RAM built into the Duo.

The console's CPU is a Hudson Soft HuC6280 8-bit microprocessor, which features integrated bankswitching hardware (driving a 21-bit external address bus from a 6502-compatible 16-bit address bus), an integrated general-purpose I/O port, a timer, block transfer instructions, and dedicated move instructions for communicating with the HuC6270A VDC. Its 16-bit graphics processor and video color encoder chip were also developed by Hudson Soft.[16] It holds 8 kB of work RAM and 64 kB of video RAM.

X (Horizontal) Resolution: variable, maximum of 565 (programmable to 282, 377 or 565 pixels, or as 5.3693175 MHz, 7.15909 MHz, and 10.738635 MHz pixel dot clock)[17] Taking into consideration overscan limitations of CRT televisions at the time, the horizontal resolutions were realistically limited to something a bit less than what the system was actually capable of. Consequently, most game developers limited their games to either 256, 352, or 512 pixels in display width for each of the three modes.[18]

Y (Vertical) Resolution: variable, maximum of 242 (programmable in increments of 1 scanline). It is possible to achieve an interlaced "mode" with a maximum vertical resolution of 484 scanlines by alternating between the two different vertical resolution modes used by the system. However, it is unknown, at this time, if this interlaced resolution is compliant with (and hence displayed correctly on) NTSC televisions.

The majority of TurboGrafx-16 games use 256×239,[17] though some games, such as Sherlock Holmes Consulting Detective did use 512×224.

Colors per palette: 16 per background palette (color entry #0 of each background palette must be the same), and 15 per sprite palette (plus transparent, which is displayed as an actual color in the overscan area of the screen)

Palette: Each sprite can use up to 15 unique colors (one color must be reserved as transparent) via one of the 16 available sprite palettes.

Layers: The HuC6270A VDC was capable of displaying one sprite layer. Sprites could be placed either in front of or behind background tiles by manipulating a bit which caused indirect pixel color entry #0 of the background tile(s) to act as transparent.

Palette: Each background tile can use up to 15 unique colors via one of the 16 available background palettes and 1 shared color (BG color #0) for a total of 16 colors per tile. The first color entry of each background subpalette is ignored. Instead, color #0's RGB value is shown in its place (the common/shared color). When a specific sprite is set to show behind the BG layer via the priority bit, all tiles that use relative color #0 (of 16) will not show BG color #0. But instead will show the sprite pixel (if not opaque).

Layers: The HuC6270A VDC was capable of displaying one background layer.

Each channel had a frequency of 111.87 kHz for single cycle of 32 samples (while not in D/A mode) with a bit depth of 5 bits. Each channel also was allotted 20 bytes (32×5 bits) of RAM for sample data.

The waveforms were programmable so the composers were not limited to the standard selection of waveforms (square, sine, sawtooth, triangle, etc.). But the use of standard waveforms, and semi-standard forms, such as a 25% pulse wave were used fairly often.

The first two audio channels (1 and 2) were capable of LFO when channel #2 was used to modulate channel #1. In theory, this could also be used to perform an FM operation, though due to other limitations, this was never done (note: LFO, like FM works by modifying an audible waveform (carrier oscillator) with an inaudible waveform (modulator oscillator), but LFO's modulator is subsonic rather than sonic (FM), so LFO will not change the carrier's timbre, just its behavior, and as a result, LFO does not really sound anything like FM.)

The final two audio channels (5 and 6) were capable of Noise generation.

Optional software enabled Direct D/A which allows for sampled sound to be streamed into any of the six PSG audio channels. When a channel is in D/A mode the frequency is as fast as the CPU can stream bytes to the port, though in practicality it is limited to 6.99 kHz when using the TIMER interrupt with its smallest loop setting (1023 cpu cycles) or 15.7 kHz using the scanline interrupt.

There is a method that combines two channels in DDA mode to play back 8-bit, 9-bit, or 10-bit samples.

The addition of the CD-ROM peripheral adds CD-DA sound, and a single ADPCM channel to the existing sound capabilities of the PC Engine.

Sound system is often mistakenly called PSG, but this is incorrect. It is Wavetable Synthesis. The fairly common use of standard and semi-standard waveforms is the most likely source of the confusion. But PSG and Wavetable do not generate sound the same way. So, even when they're both making exactly the same tone, there's still something completely different going on "under the hood." The only point at which the term PSG may ever be appropriately used when applied to this sound system is in the ability to use white noise on channels 5 and 6.

With HuCards, a limited form of region protection was introduced between markets which for the most part was nothing more than running some of the HuCard's pinout connections in a different arrangement. There were several major after-market converters sold to address this problem, and were sold predominantly for use in converting Japanese titles for play on a TG-16. In the Japanese market, NEC went further by adding a hardware level detection function to all PC Engine systems that detected if a game was a U.S. release, and would then refuse to play it. The only known exception to this is the U.S. release of Klax which did not contain this function. The explanation commonly given for this by NEC officials is that most U.S. conversions had the difficulty level reduced, and in some cases were censored for what was considered inappropriate content, and consequently, they did not want the U.S. conversion to re-enter the Asian market and negatively impact the perception of a game.[citation needed] With some minor soldering skills, a change could be made to PC Engines to disable this check.[19] The only Japanese games that could not be played on a U.S. system using one of these converters were the SuperGrafx titles which could only be played on a SuperGrafx.

Oki MSM5205 ADPCM chip with variable speed input clock, and 64 kBDRAM for audio sample storage. Only one channel of 4-bit compressed audio (decompresses to 12-bit, top 10 bits output through DAC) was supported.[20] It supports a sampling rate of up to 32.088 kHz.[21]

The PC-Engine CD-ROM interface tray has 64 kB of DRAM for storage of program code and data loaded from the CD.

The "System Card" contains the BIOS program used to boot CD media and provides functions for software to access CD hardware through a standardized interface. Later System Cards had extra RAM and updates to the BIOS.

The Duo series has the same BIOS ROM (v3.00) and RAM (256 kB total) as a PC-Engine system equipped with a Super System Card. The Duo implements the memory as a single 256 kB SRAM chip rather than the split 64 kB DRAM / 192 kB SRAM.

The list of known CD-ROM BIOS revisions are:

v1.00 - First release (HuCard, came with the PC-Engine CD-ROM Interface Unit)

v2.00 - Upgrade (HuCard, sold separately)

v2.10 - Upgrade (HuCard, sold separately)

v3.00 - Final release (built into several products and available as a HuCard - see below)

The list of known System Card releases are:

System Card v1.00 - First release. Came packaged with the original PC-Engine CD-ROM² System. Also available as a standalone purchase, in case the pack-in System Card was lost or damaged.

System Card v3.00 (aka. Super System Card) - 1.5 MbitRAM (192 kB) – RAM upgrade and BIOS update. This expands the RAM available for the CD-ROM unit to 256 kB when including the existing built in DRAM. It also offers a final BIOS update to v3.00. The PC-Engine Duo (Turbo Duo in North America) had 256 kB of RAM and the same v3.00 BIOS built into the system. Games developed for this System Card bore the title "Super CD-ROM²", and could not be played using an older System Card.

Arcade Card Pro - 17.5 Mbit RAM (2240 kB as 2 MB+192 kB) – RAM upgrade. This greatly expands the RAM available for the CD-ROM unit to 2240 kB. The BIOS revision was unchanged from v3.00. Games developed for this System Card bore the title ‘Arcade Card CD’, and could not be played using an older System Card. The Arcade Card Pro includes the extra 192 kB needed by the non Duo CD system. The 2 MB of RAM is accessed through ports or units of single 8 kB banks and is intended for graphics data storage rather than program code; its flexible addressing system allows for rapid transfer of data to VRAM.

Arcade Card Duo – 16 Mbit RAM (2048 kB) – RAM upgrade. This greatly expands the RAM available for the PC-Engine Duo system to 2048 kB. The BIOS revision was unchanged from v3.00. Games developed for this System Card bore the title ‘Arcade Card CD’, and could not be played using an older System Card. This will only work on the Duo systems, as it does not include the extra memory built into the Duo system.

Games Express CD Card – Bootleg System Card. This was released by Hacker International for play of unlicensed Games Express CD games. The GECD Card is essentially a dongle; a BIOS v3.00 based machine (like a Duo or a Super CD-ROM²) is required for running those games.

In Japan, the PC Engine outsold Sega's console. In North America and Europe the situation was reversed, with both Sega and Nintendo dominating the console market at the expense of NEC. Initially, the TurboGrafx-16 sold well in the U.S., but eventually it suffered from lack of support from third-party software developers and publishers.

Reviewing the Turbo Duo model in 1993, GamePro gave it a "thumbs down". Though they praised the system's CD sound, graphics, and five-player capability, they criticized the outdated controller and the games library, saying the third party support was "almost nonexistent" and that most of the first party games were localizations of games better suited to the Japanese market.[22] In 2009, the TurboGrafx-16 was ranked the 13th greatest video game console of all time by IGN, citing a lack of third party support and the absence of a second controller port.[23]

In 1994, NEC released a new console, the Japan-only PC-FX, a 32-bit system with a tower-like design; it enjoyed a small but steady stream of games until 1998, when NEC finally abandoned the video games industry. NEC would then partner with former rival Nintendo in making the CPU for the Nintendo 64 and Sega, providing a version of its PowerVR 2 Chipset for the Dreamcast.

A number of TurboGrafx-16 and TurboGrafx-CD games were released on Nintendo's Virtual Console download service,[24] including several that were originally never released outside Japan.[25][26] At the 2011 GDC, Nintendo announced that TurboGrafx-16 games would be available for the Nintendo 3DS's Virtual Console.[citation needed]